This invention relates to a respirator and dual disposable filter system with improved filtering capabilities, and improved wearer comfort, visibility and safety.
Standards set by the National Institute for Occupational Safety and Health (NIOSH) for lead fume environments, such as in welding operations, require that optimum breathing resistance be maintained over very long periods of time, generally five or more hours. Dust-mist protection standards set by NIOSH do not require long wear protection and can be easily satisfied with the respirator described in U.S. patent application Ser. No. 439,930. The respirator described in U.S. patent application Ser. No. 439,930 being designed for dust-mist protection, will not meet the standards set for lead fume environments. The respirator of the present invention also provides protection against other hazardous fumes including aluminum, antimony, cadmium, chromium, copper, iron, magnesium, manganese and zinc. The respirator of the present invention differs from the respirator of U.S. patent application Ser. No. 439,930 in that the respirator of the present invention contains two filter housings and filters whereas the respirator of U.S. patent application Ser. No. 439,930 has only one of these elements. The valve mechanisms of the respirator of the present invention are similar to those of the respirators of U.S. patent application Ser. No. 439,930.
When conventional respirators are used under a welding helmet or shield, the helmet facepiece contacts the filter housing to form an approximately 14.degree. angle to the wearer's face. Thus, there is a relatively large gap at the chin where light and welding spatter can enter. Also the awkwardness of this angle is uncomfortable to the wearer because he must bend his body or head toward the work in order to see. This situation exists with the more conventional helmets. There are some welding helmets that are specifically designed for use with bulky breathing apparatuses. However, the cost of replacing conventional welding helmets with specially designed helmets may be extremely high.